The present invention relates generally to electric machines and, more particularly, to insulator spacers provided proximate the connection ends of conductors above a stator core.
Electric machines may be used for a variety of applications, including in connection with automobile power trains. For example, a conventional automobile may use an electric machine as a starting motor for an internal combustion engine, or as an alternator to generate electricity and deliver power to vehicle accessories and/or charge a vehicle's battery. It is also known to use electric machines as traction motors, for example with hybrid/electric vehicles.
It is known in such electric machines to manufacture a stator assembly by using pre-formed conductors. To complete the electrical circuit, the free ends of the conductor are bent or twisted for alignment and then joined together in a particular arrangement. The twisting process, due to complex geometry and the number of conductors, may yield significant variations in spacing from one conductor to another conductor. Inadvertent electric contact between the various conductors may cause the stator assembly to not function properly. In order to accommodate these dimensional variations, the degree of conductor twisting may be minimized, resulting in an increased length of the motor and/or a reduction of power density.
The present disclosure relates to elongated insulator spacers woven between various conductors at the free ends thereof prior to twisting in a pattern that protects the conductors from touching or damaging adjacent conductors. As such, the overall length of the motor may be reduced, or the power may be increased in the same length. Further, such insulator spacers improve the durability and resultant life of the electric machine by preventing potentially damaging contact between adjacent conductors.
According to an illustrative embodiment of the present disclosure, a stator assembly includes a stator core including a sidewall extending about a longitudinal axis. A first conductor layer includes a plurality of circumferentially spaced electrical conductors defining an annular ring, and a second conductor layer including a plurality of circumferentially spaced electrical conductors defining an annular ring, the second conductor layer being positioned radially outwardly from the first conductor layer. A first insulator spacer formed of an electrically non-conductive material is interwoven between the first and second conductive layers by extending alternately between outer and inner surfaces of circumferentially adjacent electrical conductors of the first conductor layer. A second insulator spacer formed of an electrically non-conductive material is interwoven between the first and second conductive layers by extending alternately between outer and inner surfaces of circumferentially adjacent electrical conductors of the second conductor layer.
According to a further illustrative embodiment of the present disclosure a stator assembly including a stator core, and a plurality of electrical conductors supported within the stator core and extending axially between opposing first and second end portions, the first and second end portions positioned outside of the stator core, the plurality of conductors being arranged in a plurality of concentric layers. A first elongated insulator spacer is interwoven in a substantially sinusoidal path between the plurality of conductors proximate the second ends outside of the stator core, the insulator spacer being formed of an electrically non-conductive material.
According to another illustrative embodiment of the present disclosure a method of forming a stator assembly of an electric machine includes the steps of providing a stator core having a plurality of slots extending axially between an insertion end and an opposing connection end, and inserting a plurality of electrical conductors within the slots of the stator core. The method further includes the steps of positioning an insulator spacer in axially spaced relation to the stator core proximate the connection end of the stator core, the insulator spacer formed of an electrically non-conductive material, and aligning the insulator spacer with spaces intermediate the plurality of electrical conductors. The method also includes moving the insulator spacer toward the connection end of the stator core such that the insulator spacer is pushed into the spaces intermediate the plurality of electrical conductors and interwoven in a substantially sinusoidal path between the electrical conductors.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.